With the development in information communication technology, a variety of wireless communication technology has been developed. A WLAN permits wireless access to Internet in specific service areas such as home or companies or air planes by the use of portable terminals such as a personal digital assistant (PDA), a laptop computer, and a portable multimedia player (PMP) on the basis of the radio frequency technology.
These days, thanks to the increased availability of WLANs, portable terminal users such as laptop computer users are able to perform their tasks with increased mobility. For example, a user can take his laptop computer from his desk into a conference room to attend a meeting and still have access to his local network to retrieve data and have access to the Internet via one or more modems or gateways present on the local network without being tethered by a wired connection. Similarly, business travelers commonly use their portable terminals to gain access to their email accounts, to check if there is any unread email, and to read and send email.
In the initial WLAN technology, a data rate of 1 to 2 Mbps was supported by the use of frequency hopping, spread spectrum, and infrared communication using a frequency of 2.4 GHz in accordance with the IEEE 802.11. In recent years, with the development of the wireless communication technology, 54 Mbps in maximum can be supported by applying the orthogonal frequency division multiplex (OFDM) technology, etc. to the WLAN. In addition, the IEEE 802.11 has developed or is developing wireless communication technology for improvement in the quality of service (QoS), compatibility of an access point (AP) protocol, security enhancement, radio measurement or radio resource measurement, wireless access in vehicular environment, fast roaming, mesh network, inter-working with external networks, wireless network management, and the like.
The wireless network management procedure for a WLAN provides protocols relevant to the wireless network management, such as allowing a non-AP station or an access point (AP) to collect a variety of information on the wireless network or diagnosing problems of the wireless network. For example, the wireless network management procedure includes an event reporting procedure, a diagnostic reporting procedure, a presence service procedure, a base service set (BSS) transition management procedure, a flexible broadcast multicast service (FBMS) procedure, a traffic filter service (TFS) procedure, and a sleep mode procedure.
The event reporting procedure serves to diagnose states of a network in real time. The even reporting procedure in a WLAN defines a variety of events such as a transition event, a robust security network association (RSNA) event, a peer-to-peer link event, and a system log event as event request/report elements. Event request/report elements other than the system log event define various types of sub-elements. STAs supporting the event reporting procedure should store the last 5 events for the event report elements supported by the STAs after they are associated with an extended service set (ESS).
In the event reporting procedure, when a received even request frame includes requests for the transition event, the RSNA event, and/or the peer-to-peer link event and each event request includes one or more sub-elements, a requested STA contains available event report elements corresponding to a specified condition in an event report frame. On the other hand, when the specified event request does not include any sub-element, the requested STA contains all the available event report elements in the event report frame. When the available event report elements do not fit into one MAC management protocol data unit (MMPDU), the requested STA transmits remaining event report elements using additional event report frames until transmitting all the event report elements.